Coleman Furnace Repair Manual

The Coleman Furnace is a high-efficiency heating system designed for residential use, featuring advanced combustion technology, electronic ignition, variable-speed blower motor, diagnostic LED system, and multiple safety controls. Below are key sections for safety procedures, technical specifications, troubleshooting, maintenance, and repair instructions.

1. Safety Precautions 2. Model Identification 3. Technical Specifications 4. System Components 5. Diagnostic Codes 6. Common Issues & Solutions 7. Maintenance Procedures 8. Parts Replacement 9. Wiring Diagrams 10. Professional Service

Safety Precautions

Always follow safety protocols when servicing Coleman furnaces.

HazardPrecaution
Electrical ShockDisconnect power at main breaker before servicing
Gas LeaksUse leak detection solution; never use open flame
Carbon MonoxideEnsure proper ventilation; install CO detectors
Hot SurfacesAllow furnace to cool completely before touching components
Moving PartsKeep hands clear of blower wheel during operation

Model Identification

Locate model and serial numbers on rating plate inside furnace door.

  1. Open front access panel
  2. Find silver rating plate on inner door frame
  3. Record model number (e.g., Coleman DGAA077BDTA)
  4. Note serial number for parts ordering

WARNING! Always verify correct model number before ordering replacement parts.

Technical Specifications

System Components

Key furnace components and their functions.

Gas Valve: Regulates gas flow to burners. Heat Exchanger: Transfers heat to air stream. Blower Assembly: Circulates heated air. Control Board: Manages furnace operation and diagnostics. Limit Switches: Safety devices preventing overheating. Flame Sensor: Detects burner flame. Inducer Motor: Ventilation system for combustion gases.

Diagnostic Codes

LED flash codes for troubleshooting Coleman furnaces.

  1. Count LED flashes on control board
  2. Refer to code chart in furnace manual
  3. Common codes: 1 flash (ignition failure), 2 flashes (pressure switch), 3 flashes (limit circuit)
  4. Reset power after diagnosing and repairing

Tip: Document flash pattern before resetting system.

Common Issues & Solutions

Frequent furnace problems and repair procedures.

  1. No Heat: Check thermostat setting, gas supply, power connection
  2. Short Cycling: Inspect air filter, flame sensor, limit switches
  3. Blower Not Working: Verify motor capacitor, control board signals
  4. Ignition Failure: Clean flame sensor, check gas valve operation
  5. Unusual Noises: Inspect blower wheel, inducer motor, heat exchanger
  6. Poor Airflow: Replace filter, check ductwork for obstructions
  7. Gas Odor: Immediately shut off gas and contact professional

WARNING! Gas-related repairs should only be performed by qualified technicians.

Maintenance Procedures

Routine maintenance for optimal furnace performance.

Annual Inspection: Professional tune-up recommended. Monthly: Replace air filter. Seasonal: Clean flame sensor, check venting. Biannual: Lubricate motor bearings (if applicable). Yearly: Inspect heat exchanger for cracks.

Parts Replacement

Common replacement parts and installation guidelines.

PartReplacement Procedure
Air FilterSlide out old filter; insert new one with arrows pointing toward blower
Flame SensorRemove single screw; gently pull out sensor; clean with emery cloth
IgnitorDisconnect wires; remove mounting screws; install new ignitor carefully
Gas ValveShut off gas; disconnect wiring and pipes; install new valve; leak test
Blower MotorDisconnect power; remove blower assembly; replace motor; reassemble

Wiring Diagrams

Refer to specific model wiring diagram located on furnace door or in original manual.

CAUTION! Always disconnect power before accessing electrical components.

Professional Service

When to contact a certified Coleman technician.

Coleman Support: 1-800-445-8292 or www.colemanac.com

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